A forward/adjoint transport formalism for sensitivity studies
We describe a formalism for efficiently estimating the sensitivity of radiative transfer solutions to perturbations in the absorption and scattering properties of the transport medium assuming a fixed material temperature distribution. This formalism is adapted from a similar formalism commonly used in the neutron transport community. It is based upon the use of solutions to both the forward (standard) and adjoint transport equations. Given any desired integral response, one can use this formalism to obtain a first-order estimate of the change in that response as a function of any perturbation in the absorption coefficients, the scattering coefficients, and the scattering phase function. One forward transport solution and one adjoint transport solution are required for the unperturbed system. The estimate for the change in the response is expressed in terms of integrals over phase space of certain functions constructed from the forward intensity solution, the adjoint intensity solution, the absorption coefficient perturbation, the scattering coefficient perturbation, and the scattering phase function perturbation. Given a large set of perturbations, it is much less costly to use this formalism to estimate the effect of each perturbation than to solve the transport equation for each perturbed configuration. Interestingly, standard radiative transfer codes can be used to solve the adjoint transport equation, so special adjoint transport codes are not required. After describing the formalism, a simple analytic example calculation is performed to demonstrate its validity. Finally, the method is used to determine the change in the surface radiative heat flux due to changes in the multigroup (non-grey) absorption and scattering coefficients in a three-dimensional benchmark problem with anisotropic scattering.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 10139269
- Report Number(s):
- LA-UR-94-891; CONF-940625-4; ON: DE94009363
- Resource Relation:
- Conference: 6. AIAA/ASME thermophysics and heat transfer conference, Colorado Springs, CO (United States), 20-23 Jun 1994; Other Information: PBD: [1994]
- Country of Publication:
- United States
- Language:
- English
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